Telephone-exchange system



0. B. FOWLER.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JAN. 27, 1919.

1,356,704. Patented 0ct.26,1920.

1/ ven f0 7 C Mme/10a 5. Faw/er I fee CLARENCE 'B. rownnn,

STATES- OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELEGTRIQCOII- PARTIENT cor-rice,

PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Patented 0015 2 6, 1920.

Application filed January 27, 1919. SerialNo. 273,207.

To all whom it may concern:

Be it known that I, CLARENCE a citizen of the United States, .residin at New York, in the county of New ork, State of New York, have invented certain new and useful Improvements in Telephone- Exchange Systems, of which the following is a full, clear, concise, and exact description. a

This invention relates to telephone exchange systems and more particularly to such systemsin which connections are to be established between telephone lines terminating at a manual exchange and telephone lines terminating at an automatic exchange.

It is frequently the practice in such systems to employ trunk circuitsinterconnecting the exchanges over which the operator at the manual exchange, in response to a call received over a calling line terminating v thereat, may select the desired line terminating at the automatic exchange.

In systems of this nature, it is desirable to eliminate any possibility of interference resulting from any tones which may be transmitted to the operator at the manual exchange during such process.

It is the object of this invention to provide an improved system of this nature wherein the operators telephone set, although normally operatively associated with the trunk circuit upon the connection of the associated link circuit with the trunk, is eifecvice to efiectively exclude the o'perators telephone set from association with such link circuit.

In accordance with a second feature of the invention, means is provided associated with the above mentioned link circuit responsive. to the connection of the'operators telephone set to another link circuit for disconnecting the set from the first mentioned link circuit.

These and other features not specifically mentioned above will clearly a pear from the following specification and t e annexed B. amt,

-manual exchange,

drawin in which'the figure shows diagrammaticaly one embodiment of the invention as apphed to link circuitsat a manual exchange adapted for selecting over a trunk. circuit a subscribe'rs line terminating at, an automatic exchange, and for connecting subscribers lines terminating at the manual exchange with such trunk circuit.

In the drawing, a manual exchange'X is connected with the automatic exchange Y, by means of a trunk circuit C terminatm at exchange X in a dialing or callin 'jac and a connecting jack 4, and at 51c automatic exchange in suitable means adapted to select any subscribers line terminating thereat and to connect the trunk circuit therewith. The apparatus shown at the left of the dotted line 3--3- is located at the while that shown at the right thereof is located at the automatic exchange. The apparatus diagrammatically illustrated at the right of line 3-3 for extending the .trunk circuit C to the subscribers line 2, terminating at the auto- .matic exchange, may be of the type disclosed.

in Patent No.- 1,271,133 granted to H P Clausen, July 2,1918. The ti and ring conductors 29 and 30 respective yvof the trunk I circuit C may be connected directly to the conductors 29 and 30 respectively of the Clausen patent, disregarding the contact bank at. which such leads terminateand all apparatus at the left thereof.

. A dialing or calling cord circuit A and a connecting cord circuit B are rovided at the manual exchange X for selecting the line at the automatic exchange Y and for connecting a callin subscriber (not shown) with the trunk clrcuit C respectively. 1 Additional cord circuits similar to the cord circuit B may be provided at'the manual exchange for interconnecting the lines terminating thereat; the listening keys of such cord circuits may be connected to the leads 6 and 7 extending from the o erators telephone of the o erators telephone set with the cord circuit through a repeating coil 9, while relay 10 coiiperates with the dialing or calling device 11 to render the operators telephone set ineffective during the calling operation, poraneous association of such set with the cord circuit A and one of the connecting circuits similar to cord circuit B. .Relays 14,

100. set. Relay 8 controls t e' association and relay 32 prevents the contemplug 20 and the winding 0 tem'shown on the drawing:

exchange Y. The insertion ofplu 19 into jack 4,0perates relay 14 and lig ts lamp 17 over a circuit established from battery through the lamp 17, the resistance -18, the sleeve contacts of plug 19 and jack 4, the

left-hand winding of relay 14, and the contact of relay 15 to ground,

Plug 20 of the dialing or calling cord A, is thereupon inserted into dialing jack 1, thereby operating relays 8 and 16 overia circuit established from battery through the left-hand contact of relay 14, the windin of relay 16, the tip contact of jack 1 an ground. The operation of re ay 8 connects the operators telephone set inductively to the ring andsleeve contacts of plug 20 and the jack 1 through the medium of repeating coil 9.- The opening of the normal contacts of relay 16 removes the conductors associated with the tip and ring contacts of jack 4 from their normal connection with conductors 29 and 30, respectively, while the closure of the alternate contacts of relay 16 connects the ring and sleeve contacts of jack 1 to the conductors 29 and 30 respectively. I

The operator actuates the calling or dialing device 11 in the usual'manner to connect the trunk circuit C with the line circuit leading to substation 2. The first actuation of the device 11 closes the contact 12 to operate relay 10 over a circuit established from battery through the winding of relay 10 and the contact 12 of the device 11 to the ground. The closure of the alternate contact of relay 10 short-circuits the secondary winding of repeating coil 9, while the opening ofthe normal contact of such relay opens the circuit including the lprimary winding of such repeating coil. he contact 12 is closed before the contact 13 is opened, and remains closed until the calling device is restored to normal, at which time relay 10 releases and the operators telephone set is reassociated with'the ring and sleeve conductors of the cord circuit A.

The trunk circuit connecting apparatus at the exchange Y operates responsive to the opening and closing of contact 13 of device 11 in the manner described in the Clausen patent as being responsive to the dialing by relay 8 to the calling subscriber. I The reassociation of the 'operators telephone set with the cord circuit A upon the restoration of the device -11 to normal when the dialing operation is complete, enables the operator at exchange X to listen for the busy tone which, mentioned in the Clausen patent, will be encountered if the line 2 is busy.

The absence of the bus tone notifies the operator at exchange X that the called line 2 is idle, and the plug 20 is thereupon removed from jack 1, thereby disconnecting the ring and sleeve contacts of jack 1 from the conductors 29 and 30, and restoring the tip and ring contacts of jack 4 to their normal association with conductors 29 and 30 respectively. Thereupon a bridge. including the retardation coil 22, the right-hand contact of relay, 14, and the winding of relay 15, is connected across the conductors 29. and 30. However relay 15 is polarized and does not operate at this time. Upon the answer of the coiled station 2, the connecting apparatus functions in the manner described in the Clausen patent, and the consequent reversal of the battery supply connected to the trunk conductors 29 and w 30 causes the operation of the polarized relay 15. The opening of the contact of the rela 15, removes the short circuit formerly esta lished around the right-hand winding of the relay 14, thereby sufficiently. increasing the resistance of the circuit, including the supervisory lam 17, to extinguish such lamp, thereby noti ying the operator that a the called party has answered. The subsequent removal of plug 19v from jack 4 restores all apparatus to normal.

. If while the plug 20 remains in the jack 1, and the calling device 11 is in its normal position, a listening key similar tokey 21 connected to the leads 6 and 7 and included in another cord-circuit similar to cord circuit B is actuated, rela 32 is operated over a circuit extending rom the battery associated with such cord circuit through the lower contacts of the actuated listening key,

conductor 6, winding of relay-32, retardation coil 23, conductor 7 and'the upper contact of the actuated listening key to the ground. Relay 8 releases due to the short circuit established around the winding thereof, removing the operators telephone set from association with the cord circuit A, so that the busy tone which might be received over the trunk circuit C is eifectively prevented from being transmitted to any subscriber whose line might be connected with the cord circuit associated with the actuated listening key. Also the possibility of any interference caused by the operator receiving such tone While engaged in conversing with such subscriber, is prevented.

It will be evident that in this invention theoperators telephone set, although efi'ec- .to the link circuit,

tive to receivetones incident to establishing connections through the automatic 'exchange, is rendered ineffective during the actual selectin period, and that any possibility of inter erence caused by such tones is prevented.

What is claimed is: 1

1. In a telephone exchange system, a trunkcircuit, a link circuit for connection therewith, an operators plura minals, a link circuit for connection with one terminal, another link circuit for connection with another terminal, an operators telephone set, and means jointly controlled by the connection of both .link circuits with the trunk circuit for connecting the operators telephone set with one link circuit.

3. In a telephone exchange system, a trunk circuit with normally connected and normally disconnected terminals, for connection with each terminal, means jointly controlled by the connection of a link circuit with each terminal to connect the normally disconnected terminal to the trunk circuit and to disconnect the other terminal 85 therefrom, an operators telephone set, means cooperating with the above mentioned means to connect the operators telephone set with the trunk circuit, a calling device associated with the link circuit adapted for use with the normally disconnected terminal, and means controlled thereby to disconnect the operators telephone set from the associated link circuit during the operation of the calling device.

4. In a telephone exchange system, a trunk normally connected and normally disconnected terminals, a link circuit for connection with the normally connected terminal, a second link circuit for connection with the'normally disconnected terminal, an operators telephone set, a repeating coil means jointly controlled by the connection 0 the link circuits with the terminals to disconnect the normally connected terminal from the trunk circuit and to connect the normally ditional means controlled thereby for concircuit with link circuits disconnected terminal thereto, ad-' necting the operators telephoneset with the second link circuit through the repeating coil, a calling device associated with the second link circuit, and means for short-circuitng the repeating coil winding connected to /t'he link circuit thereby rendering the operators telephone set ineffective during the operation of the calling device.

5. In a telephone exchange system, a trunk circuit with normally connected and normally disconnected terminals, a link circuit for connection with the normally connected terminal, a second link circuit for connection with the normally disconnected terminal, an operators for association with either link circuit, means jointly controlled by the connection of the link circuits with the trunk circuit to disconnect the normally connected terminal telephone circuit adapted from the trunk circuit and to connect thereto the normally disconnected terminal, additionalmeans controlled thereby for connecting the operators telephone set with the second link circuit, a calling device for the second link circuit, means for preventing the connection of the operators telephone set with the second'link circuit during the oper-' ation. of the calling device, and additional means for preventing the contemporaneous association of the telephone set with both link circuits.

6. In a telephone exchange system, a trunk circuit for extending a connection from a manual exchange to an automatic exchange, a link circuit at the manual exchange for connection with the trunk circuit, a plurality .of terminals for the trunk circuit at the manual exchange, a plurality of link circuits for connection therewith, an operators telephone set, and means-controlled by the connection of a plurality with the trunk circuit ciating the operators telephone set with one of the connected link circuits.

7 In a telephone exchange system, a link circuit, an operators telep one set, means for inductively connecting such operators telephone set with the link circuit, a second link circuit, means for conductively connecting the operators telephone set thereto, and means responsive thereto to disconnect the operators telephone set from the first link circuit.

In-witness whereof I hereunto subscribe my name this 16th day of January, A I) CLARENCE B. FO'WLERL 

